[Orion] Orion - Fan Noise

[Henry Pfizenmayer]

Ran into something today that blew me away - if you use the Orion  fan
this may be of interest.

Was listening on 10 meters and had almost S7 noise that sounded like a
series wound motor running - was worst on the main rx and covered virtually
the entire spectrum on the sub rx. On the main rx it peaked around
28437 --28766 - then again at 29436 khz and was essentially gone on lower
bands. I started swinging the beam around to find where the noise was coming
from and nothing changed !!!! Unscrewed the coax from my ant switch to the
Orion and no change ! Poked the assorted antenna switches on the Orion with
only small changes. Unplugged the fan and guess what- no noise - plugged it
back in and you can hear it wind up - Called Paul Clinton - expecting to
hear "yes we had some bad fans - will send you another one " . He asked if
I had anything else plugged into the dc phono connector via a Y adapter
cable - , Yes , a couple nights ago I hooked up my old Drake CW75 keyer
because the Orion keyer and I don't see eye to eye. And I used a Y cable. I
unplugged the Y cable and plugged the fan in direct and no noise !!!! Paul
said that they had seen that - I felt that was goofy- the dc connector
should
be isolated well enough that sort of thing should not happen. Anyhow , I
happened to have a solid all metal Y from RCA male  to two RCA female -
plugged in the fan and the keyer and no noise - somehow noise is getting
back into the Orion from a common impedance in the Y  cable . Weird . Now I
know why I liked the ac fan motor on my 25 years old TR7/R7 !.

Rgds-- Hank K7HP